Mustafa Çakir

Understandings of current environmental issues: Turkish case study in six teacher education colleges

The purpose of this study is to profile future science teachers’ understandings of current environmental issues in the context of an education reform in Turkey. Knowledge base and understandings of elementary and secondary prospective science teachers about biodiversity, carbon cycle, global warming and ozone layer depletion were targeted in the study. Questionnaire surveys developed for this purpose were adapted and used in this investigation. The questionnaires were administered to 360 participants in six universities. Analysis involved frequencies, percentages and comparing means for students majoring in elementary and secondary science teaching. Analysis of variance for differences among majors and responses to different issues are also included. Findings are compared and contrasted with the previous research in other countries. The study has implications for the prospective preparation of teachers and the future of environmental literacy movement in Turkey.

The preparation of UV-cured superhydrophobic cotton fabric surfaces by electrospinning method

Electrospinning was used for the coating of the polyurethane/silica hybrid solutions on the cotton fabric surface. An ultraviolet curing process was performed on the collector by an ultraviolet lamp positioned inside the electrospinning cabin. In order to investigate the effect of fluorinated, silane-functionalized urethane (inorganic part) content on the water-repellency; five different fluorinated concentrations (10%, 20%, 30%, 40%, and 50% by weight) were used. The disappearance of isocyanate peaks during the silane-functionalized urethane synthesis was observed by Fourier transform infrared spectroscopy. Surface morphology and elemental analysis of the coated cotton fabric surfaces was investigated by scanning electron microscopy and energy dispersive spectroscopy analysis respectively. Water-repellency was evaluated by contact angle measurements. A sample that contained 50% inorganic part showed a contact angle of 154.5°. Samples were thermally characterized by differential scanning calorimetry. Glass transition temperature of the synthesized hybrid polymer increased with increasing inorganic part ratio. Additionally, abrasion resistance and crease recovery angle tests were performed to evaluate the effect of fluorinated part percentage on the mechanical and comfort properties of fabrics.

A cross-cultural validation of the Technology-Rich Outcomes-Focused Learning Environment Inventory (TROFLEI) in Turkey and the USA

Background Studies exploring the relationship between students’ achievement and the quality of the classroom learning environments have shown that there is a strong relationship between these two concepts. Learning environment instruments are constantly being revised and updated, including for use in different cultures, which requires continued validation efforts. Purpose The purpose of this study was to establish cross-cultural reliability and validity of the Technology-Rich Outcomes-Focused Learning Environment Inventory (TROFLEI) in both Turkey and the USA. Sample Approximately 980 students attending grades 9–12 in Turkey and 130 students attending grades 9–12 in the USA participated in the study. Design and method Scale reliability analyses and confirmatory factor analysis (CFA) were performed separately for Turkish and US participants for both actual and preferred responses to each scale to confirm the structure of the TROFLEI across these two distinct samples. Results Cronbach’s alpha reliability coefficients, ranging from α = 0.820 to 0.931 for Turkish participants and from α = 0.778 to 0.939 for US participants, indicated that all scales have satisfactory internal consistency for both samples. Confirmatory factor analyses resulted in evidence of adequate model fit across both samples for both actual and preferred responses, with the root mean square error of approximation ranging from 0.052 to 0.057 and the comparative fit index ranging from 0.920 to 0.982. Conclusions This study provides initial evidence that the TROFLEI is valid for use in both the Turkish and US high-school populations (grades 9–12). However, the psychometric properties should be examined further with different populations, such as middle-school students (grades 6–8).

Effect of water absorption on the wear behavior of sol-gel processed epoxy/silica hybrids

The aim of this study is to investigate the wear behavior of epoxy-silica hybrids. These hybrids were obtained through the addition of sol-gel prepared silica nanoparticles to epoxy resin. In this study, the effect of nanosilica content on the mechanical properties and wear behavior of epoxy-silica hybrid materials was investigated. Tensile strength, impact strength, hardness, water absorption and wear tests were conducted on the epoxy-silica hybrid specimens. The results demonstrated that the composition of hybrids was of significant importance on mechanical, water uptake and wear properties. Water absorption was found to be highly effective on the wear behavior of hybrids.

Coating properties of 1H,1H-perfluorooctylamine-terminated polyimides based on hexafluoroisopropylidene diphthalic anhydride and 1,4,5,8 naphthalenetetracarboxylic dianhydride

This study attempted to prepare polyimide coatings (PIs) containing 6FDA (hexafluoroisopropylidene diphthalic anhydride) and/or NTDA (1,4,5,8 naphthalenetetracarboxylic dianhydride) in various ratios. 1% of these polyimide chains were terminated with 1H,1H-perfluorooctylamine (PFOA) and PFOA, and terminated polyimide coatings (PIFs) were prepared in the same ratios as PIs. Coatings were produced on aluminum substrates by a 75-μm wire-wound applicator and thermally imidized. Finally, thermal, wear, and physical properties of PIFs and PIs were compared to each other. PIFs exhibited higher abrasion resistance than PIs due to the presence of PFOA. The increase in 6FDA content also resulted in elevated abrasion resistance. Both NTDA and 6FDA compounds improved thermal stability. The increase in NTDA content raised the Tg values of the polyimides. PIFs exhibited higher static water contact angle values than PIs, but the existence of microcracks decreased their hydrophobicity. The gloss values of PIFs were excellent. Improved values were obtained for pencil hardness, crosscut adhesion, and MEK (methyl ethyl ketone) rubbing properties for all coatings. In addition to the pencil hardness test, a pendulum hardness test was also carried out. The presence of PFOA affected pendulum hardness values positively, and the increase in the amount of 6FDA on polymer backbone improved the pendulum hardness values despite the rigidity of NTDA.

Öğretmen Adaylarının Bilimin Doğası Anlayışlarının İncelenmesi

Mevcut literature katkida bulunmak ve program gelistirme calismalarina yon gostermek amaciyla gerceklestirilen bu calisma, Fen Bilimleri alani ogretmen adaylarinin bilim ve bilimin dogasina iliskin goruslerini incelemektedir. Calismaya ilk ve orta ogretimde fen bilimleri alani ogretmeni olmak uzere ogrenim goren toplam 168 ogretmen adayi katilmistir. Katilimcilarin bilim ve bilimin dogasina iliskin anlayislari bir anket araciligi ile incelenmistir. Calismanin bulgulari bu alanda yapilan uluslararasi calismalarin sonuclari ile benzerlik gostermektedir. Sonuclar calismaya katilan fen bilimleri alani ogretmen adaylarinin genel olarak bilim ve bilimin dogasi konusunda eklektik bir dusunce yapisina sahip oldugunu gostermektedir.